The audio message remote communicator has been widely accepted as a convenient reliable means of receiving information at a remote location. Such audio receivers are readily made in a pocket size for use by doctors, security agents, delivery men, repairmen, or the like. It is desirable to be able to transmit video information into a remote location and to have a compact pocket size display receiver which is moderate in cost and has very low power consumption.
The basic problem in attempting to design such a telecommunicator display receiver is to come up with a practical means of displaying the video information. It is desired that the display have approximately a 400-line information band, and in order to practically do this in a pocket or hand-held receiver, the density of the image elements per inch must be very high. It is also desired that such a device have a memory capability which does not require high power usage or consumption. The overall power consumption of the display device must be relatively low to facilitate operation with compatibly sized batteries.
Very small diameter cathode ray tubes can be made to have the requisite image points per square inch and can be coupled with a semiconductive memory or with a silicon dioxide storage target to provide a memory capability. In each of these cases, the power input and power operational requirements are relatively high; the memory must be continuously exercised during reading operation. The recently developed gas discharge panels which have been proposed to replace cathode ray tubes for display purposes generally do not have the requisite element density per inch, and require continuous power operation for providing memory.
An alternative technology is to utilize a deformorgraphic target in which an electron beam is used to deform a polymer layer corresponding to a video signal, and the polymer layer is used to reflect light to form the display image. Such tubes are well known, but in general the polymer out-gases in the high vacuum environment of the cathode ray tube in which it is incorporated, and thus requires continuous pumping to remain effective. This device is also generally a high voltage device and the basic resolution is poor.